Daring to be different: Lotus Elan M100 vs BMW Z1

By Greg MacLeman

| 8 Sep 2020

Classic & Sports Car – Daring to be different: Lotus Elan M100 vs BMW Z1

The morning of 10 February 1989 isn’t a date that will stick in the memory of most people, bar those with birthdays or anniversaries, and maybe Dustin Hoffman (Rain Man picked up a Golden Bear at the Berlin Film Festival that evening).

But you can be sure that designers at Hethel and the Bavarian business managers would have been shedding a tear at the sight of the Mazda MX-5 slipping its cover at the Chicago Auto Show.

The car sent shockwaves through the industry, almost single-handedly reviving a segment of the market that many felt had died with the original Elan; it must have been particularly difficult for Lotus top brass that the new Japanese car took so much inspiration from their own back catalogue.

It was salt in the wound, then, that they had been beaten to the punch by a matter of months, with the brand-new M100 Elan – Lotus’ first open sports car since the Series 4 Seven – unveiled in August of that year.

The Z1’s sliding door is button-operated, while slender composite seats inside save weight

Things wouldn’t have been quite so gloomy in Munich. BMW was already much further along with its Z1 project, revealing the roadster to the world at the 1987 Frankfurt Motor Show and garnering as many as 5000 pre-orders before production began the following year.

News of a more affordable, lighter and more agile competitor can’t have been entirely welcome, but demand for the new car was strong, with order books inflated by early-bird customers who many suspected were speculators, all hoping to turn a quick buck in a booming market.

Speculative or not, buyers must have been excited to get behind the wheel of the Z1 – so named for the German word for future, zukunft, or the firm’s description of BMW Technik, Zentral Entwicklung, depending on who you ask.

The pet project of Dr Ulrich Bez, the Z1 was the first product of the newly formed BMW Technik, a think-tank focused on the emergence of new technologies and materials, and it certainly captured the imagination with its vertically sliding doors that disappeared into the sills at the touch of a button, coupled with advanced multi-link rear suspension comprising two transverse and one longitudinal control arm – the first of its type to be used in a BMW.

The chassis was special, too, and represented a seismic shift from the firm’s mainstream models. A plastic floor was bonded to the galvanised steel monocoque, which was paired with a composite undertray and body panels made from General Electrics’ Xenoy thermoplastic, while the hood cover, bootlid and bonnet were more conventional GRP, courtesy of Seger & Hoffman.

Each panel was fixed to the chassis via rubber mountings and torx bolts, which allowed for a degree of movement, and they could be fully removed with the bare car remaining driveable. BMW reckoned the whole process could be achieved in just 40 mins and encouraged punters to buy a set of replacement panels in order to quickly change the colour of the car. In practice, it represented a lost weekend for the amateur mechanic.

Only the open doors interrupt the Z1’s wedge profile

In order to offset the high cost of the car’s bodywork, chassis and suspension, the tried-and-tested drivetrain was lifted directly from the E30 3 Series.

The bombproof 2.5-litre M62 ‘small six’ came without a catalytic converter and offered 168bhp, while the five-speed gearbox shared the same ratios, albeit with a lightweight aluminium casing. A strong torque tube mated ’box to differential and added rigidity, with peppy acceleration thanks to a 3.64:1 final drive replacing the longer-legged 3.46:1 of the E30.

Despite BMW’s weight-saving attempts, there’s no escaping the fact that the Z1 is far from a featherweight, tipping the scales at 2844lb – heavier than a 325i – compared to just 2253lb for its Lotus rival.

You first get a sense of the roadster’s heft after pressing the button to retract the door, which glides beautifully into a recess in the sill with a mechanical smoothness born of over-engineering – it brings to mind a Dunhill Rollagas lighter or Montblanc pen.

The straight-six will be familiar to many BMW drivers and fires eagerly, settling to a muted and relaxed idle. The car can be driven with the doors down owing to the protection afforded by the deep sills, which is a strangely liberating feeling – like the first time you drive a convertible – but you quickly get used to the sensation. Thanks to the deep-set and supportive sports seats there’s none of the ‘Willys Jeep Fear’ under hard cornering, or any concern that you’re going to end up having to tuck-and-roll.

“The Z1 surely ranks as an opportunity missed”

Like the engine, the five-speed Getrag gearbox is a proven and rugged unit with a precise and positive action, and cycling through the gears is a joy. Encouragement comes with rising revs, and on the back-roads around the South Downs it quickly becomes apparent that Jeff Hewison’s Z1 is tight as a drum. It lacks the turbocharged mania of the Elan’s ‘four’, but there’s a surprising urgency from the larger BMW unit, which in reality is something of a workhorse. Perhaps it’s the six-pot howl that keeps your foot pinned to the accelerator.

One of the Z1’s greatest selling points was its advanced suspension system – in effect serving as a testbed for the upcoming E36 range – and in the perfectly balanced roadster it’s shown off to the fullest.

Throw it into a corner and the difference between what you expect and what you get is disarming – like a wacky Heston Blumenthal creation that swings from savoury to sweet.

And it really is sweet. Mechanical grip is there in abundance, and even body roll is kept relatively under control. One of the few black eyes among the many feathers in its cap is that, being designed primarily for the German market, the Z1 was only ever configured in left-hand drive, which checks your enthusiasm as the hedgerows close in, the road begins to narrow, and Chelsea tractors on the school run muscle their way over the white dividing lines.

Even stepping hard on the brakes doesn’t upset the clever, Rudolf Müller-designed Z-axle, which operates in such a way as to minimise squat and dive, while also offering complete control over wheel angles, including camber and toe-in. The result is tyres that remain in contact with the road even over rutted surfaces, and a quality of ride and poise that goes some way to disguising the heft of those trick doors and heavyweight sill sections.

It certainly impressed Autocar, which said after taking the car around Hockenheim in 1989: ‘Its chassis wields an ability so exceptional that your memory immediately scrambles for the names of cars that corner any better, and, after juggling with Countach, quattro and Esprit, goes blank.’

The Elan’s cabin is a little dull, but the turbo ‘four’ is potent

Of course, those road testers had yet to try Lotus’ latest offering, model number M100, which broke cover in August of that year.

Unlike the long-serving Esprit (and the Z1), the Elan was to be front-wheel drive – a first for the Hethel firm – in a massive departure from conventional wisdom. But where other manufacturers feared the looming challenges of torque-steer, engine movement and suspension geometry, Lotus’ Roger Becker saw opportunity.

The engineer pioneered what the firm labelled ‘interactive wishbone’ suspension, which used a relatively conventional A-arm arrangement, revolutionised by mounting the suspension components to an aluminium ‘raft’ using tough bushings. The outcome was wonderfully direct steering that was both light and consistent, regardless of speed; tyres that remained in close contact with the road, thanks to an unchanged caster angle; and a notable reduction in road noise and vibrations.

From almost any other manufacturer, the construction of the M100 would have been hailed as revolution – but Lotus had long been a pioneer of performance through light weight.

Like the original Elan, the M100 was built around a central backbone chassis, with a separate floorpan that was both riveted and bonded to steel outriggers, with the undertray and inner door panels adding to structural rigidity. As with the Z1, it benefited from advancement in plastics, with Ashland Chemicals contributing a new resin that was injected into nickel-plated, water-heated moulds that cut curing time by half.

For a front-drive car, the Elan’s grip and balance are superb

Just over 1000 cars per year were escaping the Hethel factory in the late 1980s, so help was needed from a major manufacturer to supply the most financially demanding components. A surprise tie-up was announced not with parent firm GM, but its Japanese partner (and commercial vehicle specialist) Isuzu, which agreed to provide the powertrain.

Despite it being shared with such mouthwatering exotica as the dullard Isuzu Gemini, the 1588cc four-cylinder engine was actually a real screamer – particularly in turbocharged form, as fitted to the launch SE and later S2 models (only a handful of naturally aspirated 1.6 models were built).

The transversely mounted ‘four’ employed multi-point fuel injection and – after being extensively fettled in Norfolk – produced a very healthy 165bhp, which was comparable to the Z1 and offered a massive advantage over the MX-5’s 116bhp, while the five-speed manual gearbox – also from Isuzu and uprated from the non-turbo variant thanks to a beefier clutch and taller final-drive ratio – proved rugged and well up to handling the Elan’s impressive power output.

It isn’t just the spec sheet that imbues a feeling of sportiness, but also the driving position, which is lower than its German rival and feels more cocoon-like – particularly when the Z1’s doors are lowered.

The seats are comfortable and the cabin surprisingly spacious, with plenty of elbow room and enough height to accommodate taller drivers. In many ways, the Elan’s dimensions feel ahead of its time, with a steeply raked windscreen and deep dash bringing to mind much younger machines – not to mention the prodigious width, dwarfing the svelte original Elan in the quest for increased stability.

“The pace of the Elan is truly surprising”

The M100’s stocky build was a departure from its lightweight predecessor, but it shares the family trait of brilliant handling and an ability to cross country quicker than all of its contemporaries, including the Z1.

Despite the pair sharing a terminal velocity of 136mph, the raucous turbocharged engine gets the Elan there a good deal more quickly; 1.4 secs separates the two in the sprint to 60mph, but the Elan feels a sight faster in the real world, covering 50-70mph in top in just 7.7 secs to the Z1’s 13.2.

The outright pace of the Lotus is truly surprising, with the turbo chiming in at 4000rpm and giving a kick up the backside comparable with a can of Popeye’s spinach, with barely discernible torque-steer.

Once on the move, progress is eye-opening, particularly when straights give way to twisting country lanes and you’re able to really exploit that trick front suspension. Unlike the more conventional rear-drive layout of the BMW, the front-drive Elan lets you push harder into bends, getting ever closer to the limits of grip.

When you do get there predictable understeer awaits – comfortable ground for buyers who grew up with hot hatches such as the Golf and 205 – as long as you don’t back off sharply mid-corner, when the M100 has been known to bite back.

The price difference between Elan and Z1 is difficult to ignore

It’s perhaps unsurprising that engineers at Lotus – more accustomed to knocking up cars on a shoestring budget – managed to make the Elan so much more affordable than the Z1. Hethel’s offering went on sale in the UK with a price-tag of £19,850, considerably more palatable – at least to those who intended to drive their cars – than the £37,728 it took to get behind the wheel of the BMW.

The gulf increased as the years rolled on, and today the price difference between Elan and Z1 is difficult to ignore; as in period, cost will be the deciding factor for many.

Ultimately, the Elan best fulfils its potential as a driver’s car, performing with all the accomplishment of a modern hot hatch minus the roof. It’s a more focused machine with a greater sense of purpose: typical Lotus.

The Z1, meanwhile, surely ranks as a missed opportunity. Only built for two years and never given the power to make the most of a beautifully balanced chassis, it was more engineering exercise than Ultimate Driving Machine.

But on a sunny afternoon, with the doors down and the wind in your hair, you couldn’t wish to be anywhere else.

Images: Tony Baker

Thanks to Club Lotus; the BMW Car Club Great Britain and Z1 model rep Jamal Blanc

Factfiles

BMW Z1

Sold/number built 1988-’91/8000
Construction Zinc-coated steel floorpan, welded inner body structure, Xenoy front and rear side panels
Engine iron-block, alloy-head, sohc 2494cc straight-six, Bosch Motronic fuel injection
Max power 168bhp @ 5800rpm
Max torque 164lb ft @ 4300rpm
Transmission five-speed manual, RWD
Suspension independent, at front by MacPherson struts rear single longitudinal arm, double transverse arms, coil springs telescopic dampers; anti-roll bar f/r
Steering rack and pinion, with speed-variable power assistance
Brakes 10¼in (260mm) ventilated front, 11¼in (285mm) solid rear discs, with servo and anti-lock
Length 12ft 10½in (3925mm)
Width 5ft 6½in (1690mm)
Height 4ft 2in (1277mm)
Wheelbase 8ft ½in (2450mm)
Weight 2844lb (1290kg)
0-60mph 7.9 secs
Top speed 136mph
Mpg 28
Price new £37,728

Lotus Elan S2 (M100)

Sold/number built 1994-’95/800 (plus 3855 1.6 and SE models from 1989-’92)
Construction steel backbone chassis, composite floorpan and glassfibre body panels
Engine iron-block, alloy-head, dohc, 16-valve 1588cc ‘four’, with turbocharger and electronic fuel injection
Max power 165bhp @ 6600rpm
Max torque 148lb ft @ 4200rpm
Transmission five-speed manual, FWD
Suspension independent, at front by double wishbones rear wide-based lower wishbones, upper transverse links; coil springs, telescopic dampers, anti-roll bar f/r
Steering power-assisted rack and pinion
Brakes 10in (256mm) ventilated front, 9¼in (236mm) solid rear discs, with servo and anti-lock
Length 12ft 6in (3803mm)
Width 6ft 2in (1885mm)
Height 4ft ½in (1230mm)
Wheelbase 7ft 4½in (2250mm)
Weight 2253lb (1023kg)
0-60mph 6.5 secs
Top speed 136mph
Mpg 20
Price new £19,850